This invention relates to microstrip antennas which are conformable and have a low physical profile, and can be arrayed to provide near isotropic radiation patterns.
Compact missile-borne antenna systems require complex antenna beam shapes. At times, these beam shapes are too complex to obtain with a single antenna type such as slots, monopoles, microstrip, etc., and requires a more expensive phased array.
Studies indicate that a less expensive approach can be realized in a multi-mode antenna. A multi-mode antenna is a design technique that incorporates two or more antenna types into one single antenna configuration, and uses the unique radiation pattern of each antenna type to provide a combined desired radiation pattern. This requires techniques for exciting two or more antenna modes with one single input feed and also for controlling the excitation of the mode of each antenna type in order to better shape the combined radiation pattern.
There are various prior type multilayer microstrip antennas. However, all these prior antennas are multiresonant having frequencies intentionally tuned apart and are not for the purpose of radiation enhancement of the same frequency. The prior antennas use either a plurality of feeds or a variety of antenna element sizes and shapes to provide multifrequency, or wide bandwidth.